Can't Append?

Okay so a) I have no idea what I'm doing. b) I'm on a mac and my keyboard doesn't have all functionality so my view is weird sorry, c) why can't I get the mesh to append? I've tried the nude top and sweater, and neither work. I used marvelous designer for my mesh and did everything as I was supposed to, so I'm not really sure what it is that I'm doing wrong. If anyone can give me some advice, I'd appreciate it. I can only really find tutorials on AF tops.

pic here